The JWST early galaxy crisis resolved by a reionization degeneracy
Fuente:
arXiv
Enregistré dans:
| Auteurs principaux: | , |
|---|---|
| Format: | Preprint |
| Publié: |
2026
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866914530910535680 |
|---|---|
| author | Wang, Zihan Shan, Huanyuan |
| author_facet | Wang, Zihan Shan, Huanyuan |
| contents | JWST's discovery of unexpectedly bright $z>10$ galaxies has triggered claims that standard $Λ$CDM cannot reproduce their abundances, while estimates of the ionizing escape fraction $f_{\rm esc}$ at $z>6$ have spanned a factor of four for over a decade. Here we show that both tensions arise from a structural degeneracy in reionization equations: global observables constrain only the product $f_{\rm esc}\times f_{\star,0}$ (peak star formation efficiency), not individual parameters. We demonstrate that this degeneracy, previously considered a limitation, provides a precise diagnostic framework. By leveraging JWST UV luminosity function shapes to independently constrain $f_{\star,0}$, we derive robust bounds on $f_{\rm esc}$. Joint profile-likelihood analysis across Gaussian, log-normal, and duty-cycle burst scatter models excludes the proposed crisis threshold ($\varepsilon > 3.5\%$) at $4.5σ$ confidence, with stochastic star formation histories strengthening rather than weakening the result. Combining these constraints with constant and evolving $f_{\star,0}$ measurements yields the first empirical reconstruction of $f_{\rm esc}(z)$ across $z=7$--$12$. A constant-efficiency scenario ($f_{\rm esc}\approx 10$--$16\%$) connects smoothly to low-redshift direct detections, whereas an evolving scenario ($f_{\rm esc} \approx 6\%$ at $z=12$) conflicts with low-metallicity ISM porosity expectations. JWST Cycle 3--4 will distinguish these pathways at $>2σ$, transforming a long-standing fundamental inference barrier into a powerful quantitative probe of early-universe physics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_03635 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | The JWST early galaxy crisis resolved by a reionization degeneracy Wang, Zihan Shan, Huanyuan Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies JWST's discovery of unexpectedly bright $z>10$ galaxies has triggered claims that standard $Λ$CDM cannot reproduce their abundances, while estimates of the ionizing escape fraction $f_{\rm esc}$ at $z>6$ have spanned a factor of four for over a decade. Here we show that both tensions arise from a structural degeneracy in reionization equations: global observables constrain only the product $f_{\rm esc}\times f_{\star,0}$ (peak star formation efficiency), not individual parameters. We demonstrate that this degeneracy, previously considered a limitation, provides a precise diagnostic framework. By leveraging JWST UV luminosity function shapes to independently constrain $f_{\star,0}$, we derive robust bounds on $f_{\rm esc}$. Joint profile-likelihood analysis across Gaussian, log-normal, and duty-cycle burst scatter models excludes the proposed crisis threshold ($\varepsilon > 3.5\%$) at $4.5σ$ confidence, with stochastic star formation histories strengthening rather than weakening the result. Combining these constraints with constant and evolving $f_{\star,0}$ measurements yields the first empirical reconstruction of $f_{\rm esc}(z)$ across $z=7$--$12$. A constant-efficiency scenario ($f_{\rm esc}\approx 10$--$16\%$) connects smoothly to low-redshift direct detections, whereas an evolving scenario ($f_{\rm esc} \approx 6\%$ at $z=12$) conflicts with low-metallicity ISM porosity expectations. JWST Cycle 3--4 will distinguish these pathways at $>2σ$, transforming a long-standing fundamental inference barrier into a powerful quantitative probe of early-universe physics. |
| title | The JWST early galaxy crisis resolved by a reionization degeneracy |
| topic | Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2605.03635 |